Methods and systems for a photonic interposer are disclosed and may include receiving one or more continuous wave (CW) optical signals in a silicon photonic interposer from an external optical source, either from an optical source assembly or from optical fibers coupled to the silicon photonic interposer. The received CW optical signals may be processed based on electrical signals received from the electronics die. The modulated optical signals may be received in the silicon photonic interposer from optical fibers coupled to the silicon photonic interposer. Electrical signals may be generated in the silicon photonic interposer based on the received modulated optical signals, and may then be communicated to the electronics die via copper pillars. Optical signals may be communicated into and/or out of the silicon photonic interposer utilizing grating couplers. The electronics die may comprise one or more of: a processor core, a switch core, or router.